Report from MSTRS 

MOVES Review Workgroup

Clean Air Act Advisory Committee Meeting

January 12, 2011

John Koupal

Director, Air Quality & Modeling Center

U.S. EPA Office of Transportation and Air Quality
What is MOVES?

 Motor Vehicle Emission Simulator

 Estimates emissions & energy use from all 

on-road sources over multiple scales

Replaces MOBILE6.2 as EPA’s official on2 Replaces MOBILE6.2 as EPA’s official onroad emissions model for SIP and 

conformity determinations
Why Does EPA Develop Models?

 Mandated by Clean Air Act

 Must maintain & update emission factors every 3 years

 EPA must provide tools for state and local air agencies

 Analyses required for new rules

 Quantify emission baseline & reductions

3

 Quantify emission baseline & reductions

 Provide input for air quality, cost/benefit analyses 

 “What-If” analyses

 Understand mobile source emission trends and their 

contribution to overall inventory

 Evaluate potential for new national, regional and local 

policies

 Repository of emissions and activity information
Why did EPA develop MOVES?

 MOBILE series of models obsolete and 

increasingly difficult to maintain

 Needed platform that allowed easier 

updates with new emissions, fleet and 

activity data

4

 Wanted to develop platform that could 

include all mobile sources

 U.S. National Research Council 

recommendations
Why MOVES? continued

 In “Modeling Mobile Source Emissions” (2000), 

National Research Council made several 

recommendations to EPA to improve modeling:

 Support for smaller-scale (project level) analysis 

 Improved characterization of high emitters, heavyduty vehicles and nonroad sources

5

duty vehicles and nonroad sources

 Improved characterization of particulate matter and 

toxics

 Improved model evaluation and uncertainty analysis

 Improved ability to interface with other models

 These recommendations became the primary 

objectives for MOVES
Pollutants in MOVES

 HC (THC, NMHC, NMOG, TOG, VOC)

 CO

 NOx(NO, NO2)

 NH3

6

 NH3

 SO2

 PM10,2.5 (OC, EC, sulfate, brake, tire)

 GHG (CO2, CH4, N2O)

 Toxics 

 Energy (total, petroleum, fossil)
Emissions Processes in MOVES

 Running

 Start

 Extended Idle (“hoteling”)

 Evaporative 

Permeation, Vapor Venting, Liquid Leaks

7

 Permeation, Vapor Venting, Liquid Leaks

 Refueling

 Vapor loss, Spillage

 Crankcase

 Tire Wear

 Brake Wear
MOVES is Based on Latest Data

 EPA reviewed data from hundreds of 

thousands of cars and light trucks 

 Inspection/Maintenance, RSD, historical lab data

 Landmark study of gasoline PM in Kansas City 

8

 Landmark study of gasoline PM in Kansas City 

 First use of portable emission measurement 

systems (PEMS) to capture on-road heavyduty truck emissions

 New data drives updated emission estimates
Example NOx Results 

(MOVES2009)

 On-road data on heavy trucks shows 

higher emissions than MOBILE6 

estimated from cert data

 Extended idle emissions become 

significant share of heavy-duty 

inventory in future

Fulton County (Atlanta) - NOx

0

10,000

20,000

30,000

40,000

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6

M6

M6

HD

HD

LD LD

Extended 

Idle=34%

Salt Lake County - NOx

0

5,000

10,000

15,000

20,000

25,000

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6

M6

M6

HD

HD

LD LD

Cook County (Chicago) - NOx

0

20,000

40,000

60,000

80,000

100,000

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6

M6

M6 HD

HD

LD LD
 Kansas City program found high gas 

PM emissions esp. at cold temps

 New data on heavy trucks shows 

higher deterioration than MOBILE6

 MOVES accounts for impact of 

vehicle speed – MOBILE did not 

Fulton County - PM2.5

0

300

600

900

1200

1500

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6 M6

M6

HD

HD

LD LD

Example PM2.5 Results 

(MOVES2009)

Salt Lake County - PM2.5

0

150

300

450

600

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6 M6

M6

HD

HD

LD LD

Cook County - PM2.5

0

1000

2000

3000

4000

2008 2015 2020

Annual Tons

MOVES

MOVES

MOVES

M6 M6

M6

HD

HD

LD LD
Modal “Binning” Approach

 Advancement required to meet emerging 

analysis needs

 Any driving pattern can be modeled 

 Adds major flexibility compared to MOBILE

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 Allows direct use of data from many 

sources

 Laboratory, I/M programs, RSD

 Independent validation has shown good 

results even for macroscale applications
HC Emission Rates By Bin

Source Bin: LDV Gasoline / 1996 MY 

10

100

HC Mean Emission Rate (g/hr)

0-3 year old 4-5 year old

< 25 mph 25 - 50 mph > 50 mph

0

1

braking

idle

< 0

0-33-66-9

9-12

> 12

< 0

0-33-66-9

9-12

12-1818-2424-30

>30

< 6

6-12

12-1818-2424-30

>30

VSP (KW/tonne)

HC Mean Emission Rate (g/hr)
Distribution of Operating Time by Bin

Light-Duty Cars and Trucks

0.20

0.25

0.30

Fraction of Operating Time

Rural Freeway Urban Freeway

Rural Arterial Urban Arterial

< 25 mph 25 - 50 mph > 50 mph

0.00

0.05

0.10

0.15

braking

idle

< 0

0-33-66-9

9-12

> 12

< 0

0-33-66-9

9-12

12-1818-2424-30

>30

< 6

6-12

12-1818-2424-30

>30

VSP (KW/tonne)

Fraction of Operating Time
500.00

550.00

600.00

650.00

700.00

CO2 (g/mile)

Transient driving Smooth driving

CO2Impact of Traffic Smoothing

200.00

250.00

300.00

350.00

400.00

450.00

0 10 20 30 40 50 60 70 80

average speed bin (mph)

CO2 (g/mile)

Transient Driving

Smooth Driving
MOVES History

2000 - NRC recommends complete overhaul of EPA mobile source models

2001 - EPA publishes white paper on MOVES for stakeholder and peer review

- EPA begins developing design with input from stakeholder working group

2002 - MOVES “shootout” “shootout” identifies identifies best practices best practices for modal modeling for modal modeling

2005 - First version of MOVES released – focused on energy and GHG only

- Kansas City PM study completed

2007 - Demonstration version of full on-road MOVES released 

- Established new FACA workgroup to review criteria/toxic emission inputs

2009 - Draft (MOVES2009) released in April

- Final (MOVES 2010) released in December

2010 - MOVES2010a (reflects 2012-2016 LD GHG rule)
MOVES Review Workgroup

 Formed by MSTRS to provide input to EPA on 

MOVES development

 15 meetings 2007-2010

 Workgroup members represented wide range of 

stakeholders

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 Reviewed and provided comments on MOVES 

inputs and algorithms

 Recommendations were incorporated in subsequent 

versions of MOVES

 MSTRS voted to forward to CAAAC
Workgroup Final Comments & 

Recommendations (1 of 2)

 MOVES overall structure is solid

 Provides good deal of flexibility

 MOVES validation and corroboration work 

has been helpful and should continue

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has been helpful and should continue

 EPA has compared MOVES results to a variety of 

independent datasets; recommends other 

organizations undertake this as well

 EPA should budget funds for ongoing improvement

 Continue to obtain feedback from a variety 

of users, and incorporate this feedback 

into model
Workgroup Final Comments & 

Recommendations (2 of 2)

 EPA needs to continue model updates

 Emission rates, activity profiles, as well as features

 New rules (e.g. 2012-2016 LD GHG)

 Expanded air toxics

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 Expanded air toxics

 Reduce model run time 

 EPA needs long-term data collection plan

 EPA needs to budget and plan for continued data 

collection

 EPA needs to seek data from other sources as well

 Focus on known uncertainties in the model
How EPA is addressing workgroup 

comments: Model Validation

 Comparison of MOVES fuel consumption 

results vs. fuel tax data

 Direct check of GHG emissions

 Provides top down check on model fleet, activity data 

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that applies to criteria as well

 Comparison of emission rates vs. 

independent data 

 Multiple cities – RSD, I/M, dyno data

 Report to be published 

 Air quality/dispersion studies in progress
National Fuel Consumption Comparison

80

120

160

Billion Gallons

Tax Data Final MOVES

Gasoline

0

40

80

20002001200220032004200520062007

Year

Billion Gallons

Diesel
LDV NOx Fuel-Based Emission Rates by Age

MOVES vs. Chicago RSD (2004)

8

10

12

14

NOx (g/kg fuel)

Chicago RSD

MOVES 2010

0

2

4

6

8

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

NOx (g/kg fuel)

Age
LDV NOx Fuel-Based Emission Rates by Age

MOVES vs. Atlanta RSD (2008)

20

25

30

NOx (g/kg fuel)

Atlanta RSD

MOVES 2010

0

5

10

15

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

NOx (g/kg fuel)

Age
MOVES Calendar Year 2005 HDD NOx vs. Speed

independent verification vs. CRC E-55 results

80

100

120

140

NOx [g/mile]

DRAFT MOVES

E55 HHD 56000 lb

Final MOVES

0

20

40

60

0 10 20 30 40 50 60 70 80

Average speed [mph]

NOx [g/mile]
How EPA is addressing workgroup 

comments: Model Updates

 Database approach facilitates faster 

updates in response to new data

 Updates requires careful consideration of 

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 Updates requires careful consideration of 

the policy implications and technical 

justification for a model change. 

 EPA will coordinate official releases taking 

into account the timing needs of SIP analyses 
How EPA is addressing workgroup 

comments: Long Term Data Collection

 Rolling out new advancements in capturing real-world 

emissions

 Evaporative Leak Detection Study (2008-10)

 Method developed to detect high evap vehicles using RSD

 Confirmed using portable SHED

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 Confirmed using portable SHED

 Developing way to apply to much larger RSD datasets

 Houston Port Drayage Study (2009-10)

 First to implement hybrid of RSD and PEMS

 Tier 2 PEMS Study (2010+)

 RSD conducted at 6 sites around Metro Detroit (~80,000 hits)

 PEMS testing planned on Tier 2s selected based on RSD

 Considering additional cities for 2011/2012
• Evaporative vapor emissions 

either contained, or leaking

• In collaboration with CRC and 

Colorado, developing 

groundbreaking approach to 

quantifying frequency of evap

Evaporative “Leaker” Field Study

quantifying frequency of evap

leakers

• Developed method to find evap

leakers using roadside remote 

sensing

• Verified using portable SHED 
RSD equipment

Houston Port HD Drayage Study

• ~ 4,000 RSD hits on 1,900 trucks entering port

• PEMS testing on sample of these, stratified by emission level

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PEMS Vehicle Example

MY 1994 Freightliner

Exhaust 

System

PM Proportional 

Semtech_DS Sampler System PM Filters

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On-Road NOx Data – Roundtrip from Port of Houston

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Visit the MOVES website:

http://www.epa.gov/otaq/moves.htm

 Software, technical documentation, conference and meeting 

presentations, and other helpful background materials